The invention relates to an X-ray image apparatus for conducting fluoroscopy or radiograph by X-ray, especially an improvement of the X-ray image apparatus for conducting fluoroscopy or radiograph from various directions while allowing the apparatus to rotate around an examinee or subject to be examined.
There is known an X-ray image apparatus, which is a combination of an X-ray tube and an image intensifying TV camera, for conducting fluoroscopy or radiograph for an examinee to mainly medically examine the examinee. The X-ray image apparatus may be rotated around the examinee to conduct fluoroscopy or radiograph from various directions. In this case, if the center of rotation of the X-ray apparatus does not coincide with an observing area to be examined, the locations of the observing area shown in the different images taken from the various directions become different to make observation of the images difficult.
Therefore, it is required to adjust the height and so on of an examination table on an examination base to allow the observing area to coincide with the center of rotation of the X-ray apparatus. Conventionally, an operator considers a location of the observing area based on a knowledge of anatomy and experiences, and manually adjusts so that the center of rotation of the X-ray apparatus coincides with the location of the observing area.
However, even if the operator is a skilled person, it is very difficult to estimate the location of the observing area in a body of the examinee. Practically, the observing area can not be located in the center of the image. Therefore, conventionally, the location is roughly set, and the filming or observing range is set greater than the actual observing area. As a result, an X-ray is irradiated to unnecessary portions, which may cause excess amount of exposure to the X-ray.
The present invention has been made in view of the above problems, and an object of the invention is to provide an X-ray image apparatus, which can correctly take the position of a subject to be observed.
Another object of the invention is to provide an X-ray image apparatus as stated above, wherein the center of rotation of the X-ray apparatus can be set easily according to the position of the subject.
Further objects and advantages of the invention will be apparent from the following description of the invention.